The present invention relates generally to expanding the data width of a computer graphics system. More particularly, the present invention relates to extending the data width of a computer graphics system for displaying extended precision or increased dynamic range in simulated graphics.
Infrared optics, cameras, telescopes and viewfinders have become relatively less expensive and more prevalent in recent years. Specifically, infrared (IR) is used extensively in such applications as military viewfinders, night vision goggles, vehicle night displays and similar applications.
Frequently, the military and other organizations train pilots or personnel who desire to be able to effectively use vehicles and IR equipment. It is preferable to be able to train these personnel in simulated equipment because of the reduced cost. Accordingly, it is important to be able to simulate sensor imagery in training situations such as the simulation of cockpit displays in a vehicle simulation environment for aircraft, ships and tanks. In addition, it is valuable to simulate IR imagery for guided missile applications.
Many entities, such as the US armed forces and commercial training installations, currently utilize such vehicle and IR simulations. These groups are actively seeking to update outdated and more expensive workstation-based equipment with PC-based simulation equipment and other off the shelf simulation equipment. PC-based solutions have generally been unable to simulate extended precision graphics and/or the IR dynamic range because conventional off-the-shelf graphic chips for PCs do not have the increased data width channels required for effective extended precision or increased dynamic range simulation.
The precision requirements for high precision color graphics, monochrome, and IR have traditionally been solved using custom processors with built-in high data width channels of 16 or more bits and frame buffers built to store the high precision image. Such systems are relatively rare and are costly. System designers have generally believed that where a high precision channel was needed, a processing channel with the corresponding data width should be provided. If 16 bits of precision has been needed, than a hardware defined channel that includes a 16-bit data width has been built into the system. Including a special channel that is only used for a specific purpose (such as IR) increases the cost of the overall computer graphics system.
To solve these problems and produce a high fidelity simulation (especially for IR), a system must meet the following criteria. The solution must provide a well-behaved visual output that is devoid of distracting artifacts, and have a large dynamic range to represent very hot to very cool objects in infrared simulations. In addition, numerical accuracy must also exist across the full dynamic range.
The invention provides a method for extending the data width of a graphics processing channel in a computer graphics system. The method includes the first step of providing a plurality of graphics processing channels having pre-defined output widths. The next step is combining at least a portion of an output from at least two of the plurality of graphics processing channels. Another step is defining at least one extended graphics processing channel with an extended data width. The extended graphics processing channel can be formed with output portions from the plurality of graphics processing channels.
In accordance with another embodiment of the present invention, the system includes a method for increasing the data width of a graphic system for rendering polygons having polygon vertices and intensities associated with the polygon vertices. The first step of the method is providing a plurality of graphics channels having a defined channel data width. The next step is dividing the intensities of the polygon vertices into a base and an offset. Accordingly, at least one extended data width graphics channel is created by processing the base and offset through separate graphics channels. Yet another step is combining the results of the processing of the base and offset to produce an extended data width for the polygons.
In accordance with another embodiment of the present invention, the system may include a method for increasing the dynamic range of a graphic system for rendering polygons. The method comprises the first step of providing a plurality of graphics channels. The next step is restricting the dynamic range for separate polygons to a subset of the graphic system""s entire dynamic range. Another step is increasing the dynamic range of the plurality of graphic channels by using a base and offset to represent the restricted dynamic range for separate polygons.
Additional features and advantages of the invention will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the invention.